umm, Is there any way of putting the velocity at 0 mph when not detecting anything? Cause here(when I experimented with it) when I did not move my hand, it still showed 2 mph & that's not acceptable in some cases.

It's with the timer 2, that's for sure. But before I make the initial values as 0mph, I need an expert opinion on this & a better way of doing this. & showing 2mph for a static body's sort of absurd. But that's mathematics going in there. I confused myself on this. Just started studying Timers

Is there a way of increasing the range of the Doppler radar? As in the data sheet of the Doppler radar(that I bought from an Indian market) shows a maximum sensing range of 20ms . But when I tested it on road, it gave me hardy1.5-1.8ms sensitivity. The parallex X-band sensor have a range 2.4-9m approx. I need to increase the range of my Doppler since I cannot get a parallex model whose sensitivity range can be controlled with a trim pot.

Also what you reflect from, smooth metal is best and for testing a corner reflector will send the most back. If you take a box and cut so there are 3 sides together making a corner then line the inside of that with smooth foil (try not to wrinkle) you will have a cheap corner reflector. Make it not small. Even if the reflector is not pointing directly at the source, the geometry will send the waves back. It works with light, it should work with radar.

Last is movement. The object must move relative to the radar either toward or away though sideways can be mixed in.

No 5 volts is maximum. & currently, since I'm using it for vehicle speed measurement, you can expect the worse conditions. Any type of vehicle's surface from Indian Roads shall be the reflecting surface.